I have a .net 2.0 C# Project.
I have a Treeview with 2 Nodes, each of them has many child nodes.
When you click on a child node, a PDF is displayed in a webbrowser control depending on the properties of the node.
Fine, but the problem is that when both Nodes are expanded, and I click on a child node, the other node gets collapsed! I don't have any code that collapses any node of the treeview, but somehow it happens! I also had a look at the BeforeCollapse Event, but somehow it doesn't fire, alltough the other node collapses!
Can anyone imagine why this happens?
I would be very grateful if anyone can teach me how to prevent this happening!
Thank you very much!
I stopped using the WinForms TreeView some time ago because of it's limits and quirks.
My favorite replacement is the open-source TreeViewAdv:
TreeViewAdv on Source Forge
TreeViewAdv on CodeProject
This happens if the TVS_SINGLEEXPAND style is ON for the treeview. Try setting the HotTracking property to false.
Related
I have a treeview control, the nodes and their children of which I populate on the server side from a DataTable.
How do I expand any node of the control upon click of it's rendered text?
Altering the TreeNodeSelectAction property of the node doesn't help.
I know that this property works for Tree View Controls that are not populated dynamically.
Any help is appreciated.
Sorry forgot getting back to this. I messed around using the built in "TreeView_ToggleNode" javascript function, that gets rendered along with the TreeView Control. Got exactly what I needed.
I have a treeview control on an asp page. Everytime I select a node, be it root node or child node, the entire tree is displayed again under the tree. If I go on selecting nodes on the tree, no matter which one I select, a duplicate tree is displayed under it. I have written no events so far. It is some property that I am missing out on. Please help!
Is this tree being created on page load by any chance? If so, test (!isPostback) on PageLoad in code behind before creating it. If not, then you need to provide more code. Include details of event handlers for the control etc.
I want to show the expand option against a tree node even if the node has no children. Is this possible?
(The expand option being the little plus sign in a box to the left of the node.)
If your purpose is to dynamically load children nodes when expanding the best solution is to add a fake child nodes to all the leaf nodes. Then replace the fake node with real ones when needed.
Try it with property TreeNode.PopulateOnDemand = true; - this is ideal for dynamically created trees and it adds plus sign icon also to node with no children.
Sorry this is not a direct answer to your question, but I do feel it is relevant.
Why would you want to do this? It is confusing for the user.
(I have just been through exactly the same process in another environment and user feedback was "This item is broken and won't let me see what's underneath like the other ones do").
In short, I would recommend evaluating the requirement carefully before you proceed.
I want to create an expandable empty treenode in C#, i.e. a treenode which is empty and has the [+] sign beside it. The reason is because initially it is empty, but once a node is clicked, I want to populate it with many child nodes.
The only problem I am facing is that empty treenodes aren't expandable, so I don't know what to do. Is there a way to solve this problem, or are there any workarounds?
You have to redraw the tree itself, or create an empty node and simply remove it when the parent node is expanded.
Personally, I'd go for option b). I've done this before, a while ago and thanks to the events raised by the TreeView it pretty easy to accomplish.
You can give the empty node a value like 'Loading...' so it gives some feedback to the user as well. :)
Add a dummy child node, and remove it when you expand.
Have a look at Josh Smiths excellent tutorial on treeviews. It allows lazy loading of child tree nodes by having a dummy node that is removed upon expansion.
I am using MVVM for a WPF app and I have a Telerik RadTreeView, and when I collapse a parent, I'd like to recursively collapse all children (and their children, etc) so that when I expand the parent again, I don't see any grandchildren, because all children are collapsed. Is there a property of the RadTreeView that Can accomplish this, or any relatively easy alternative way? Thanks.
Stumbled across this question searching for some other RadTreeView related topics.
Based on the current Telerik RadTreeView Documentation:
When you need to expand or collapse all the items recursively for a given item use the ExpandAll() and CollapseAll() methods of the RadTreeViewItem respectively. When you need to expand/collapse all the nodes in the tree use ExpandAll() and CollapseAll() methods of the RadTreeView.